Modern computing devices include ever-increasing processing power combined with improved ability to sense and interact with the surrounding environment. As a consequence of such improved capabilities, many computing devices are adopting new input modalities such as touch computing and gesture-based computing.
User interface gestures may include touch-based input gestures such as tapping, swiping, and otherwise manipulating a touch surface of a computing device. User interface gestures may also include input gestures made without physically touching the computing device, including moving the user's body, limbs, hands, or fingers to command user interface actions. Such movement-based input gestures are sometimes called perceptual or air gestures.